Leveling-rod.



E. S. MARTlN.

LEVELING ROD.

APPLICATION FILED MAR-7,19l3- 1,220,358. Patented Mar. 27, 1917.

Z LQJ.

a; mama.

UNKTED TATE PATENT @FFIQFZ.

ERNEST S'. MARTIN, OF CHICAGO, ILLINOIS, ASSIGNOB TO LEWIS A. NICHOLS,OF

CHICAGO, ILLINOIS.

LEVELING-ROD.

Application filed March 7, 1913.

To all whom it may concern Be it known that I, ERNEST S. MARTIN, acitizen of the United States, residing at Chicago, in the county of Cookand State of Illinois, have invented certain new and useful Improvementsin Leveling-Rods, of which the following is a specification, referencebeing had to the accompanying drawings, forming a part thereof.

The purpose of this invention is to provide a leveling rod adapted tosimplify the operation of leveling as performed in surveying, by givinga direct indication of the actual elevations of the various points atwhich readings are taken, and thus eliminating the usual computationrequired for determining such actual elevations. It consists of thefeatures and elements described and shown in the drawings as indicatedby the claims.

In the drawings z- Figure l is a diagram illustrating the mode of use ofthe leveling rod which is the subject of this invention.

Fig. 2 is a front elevation of a leveling rod embodying this invention.

Fig. 3 is a side elevation of the same partly in section.

Fig. 4: is a detail section at line & on Fig. 2.

Fig. 5 is a detail section at line 55 on Fig. 2.

Fig. 6 is a perspective detail view of a removable unit marker for theleveling rod.

As is well understood by those familiar with the art of surveying, theprocess of leveling involves, first, setting up and adjusting thetelescope, A, to a level position, next determining its elevation withrespect to some assumed base, such as sea level or lake level, and thenby sighting through the telescope, A, upon the usual form of levelingrod set up at different points along the line whose profile is to bedetermined, noting the height of the instrument, A, abovesaid variouspoints as measured by the graduated rod. For this purpose, therefore,the rod is always graduated from the bottom upward; its reading at thepoint intersected by the line of sight of the instrument, A. is ameasure of the distance from this line of sight to the foot of the redas it rests on the ground at the point whose actual elevation isrequired. This distance when subtracted from the total ele-Specification of Letters fatent.

Patented Mar. 27, 1917.

Serial No. 752,590.

vation of the instrument above the assumed base, viz: sea level or lakelevel, thus gives the actual elevation of the particular point abovesuch base. It may be noted that in most cases where a previous surveyhas been run, the assijimed base for the leveling operation is not sealevel or lake level but is the previously determined elevation of somepoint commonly called a bench mark with respect to such sea or lakelevel; but for determining the actual elevations of various points alongthe line the leveling rod readings at this point must be subtractcd froma similarly taken reading upon the bench mark, and then added to theknown elevation of such bench mark; or other equivalent computation mustbe made to determine the actual elevations of the sev ,eral points.

It is the object of the present invention to eliminate practically allof the computation above referred to. Referring to Fig. 2, it will beseen that the leveling rod, 13, is provided with a slidably extensiblefoot, 0, which may be secured in any position within its range ofmovement by a clamping screw, C If desired, the rod may be also providedwith a similarly slidable extension member, D, which will serve simplyfor in creasing the length of the rod if necessary in use; the member,D, is likewise provided with a clamping screw shown at D The forwardfaces of the rods, B and D, are divided in units of any desired length,such as feet or meters, and subdivided into equal parts of such units,preferably decimal parts. But the unit numerals are not permanentlyfixed in their places but are printed or painted upon removable markers,E, and to avoid contact of the sliding guides, C and D with thesemarkers, E, as well as to protect the other graduations of the rod fromwear. the graduated surfaces are preferably made channeled in form, asindi ated in Figs. 4L and 5.

The purpose of these various features may be most clearly indicated byan example of the mode of use of the device. Suppose the previouslydetermined eleva tion of the bench mark, F, (see Fig. 1) to be 109.7feet above sea level, then With the leveling instrument set up as shown,and with the foot, G, of the rod on the bench mark, F, the graduatedportion, B, is adjusted vertically with respect to the foot,

C, until the line of sight from the instrument, A, intersects the scaleat one of the seven-tenths marks. It will be noted that the decimalgraduations number clownwardly along the rod,- so that if the numeral 9is placed atthe first unit mark above the seven-tenths mark sightedupon,

the apparent reading of the rod will be 9.7, and this will be understoodas 109.7, which is the actual elevation of the bench mark, F, Theremainder of the graduated scale of the rod is now supplied withconsecutively arranged numeral markers at the unit points, as indicatedin Fig. 2, and with the foot piece, C, securely clamped in its adjustedposition by means of the clamping screw, G the rod is carried to thefirst point, G, whose elevation is to be determined. Then by rotatingthe telescope of the instrument at, A, so as to sight upon the rod inthe new position at, G, the readings will indicate directly the actualelevation of this point, (i; for if the point is higher than the benchmark, F, the line of sight will intersect the rod at a point below the9.7 mark, giving a proportionately higher reading; and if the point, G,is lower than the bench mark, F, the reading will come nearer the top ofthe rod and its numerical value will be lower proportionately. In asimilar manner additional readings are taken on other points along theline whose profile contour is to be determined, and in each instance thereading of the leveling rod will furnish directly the informationdesired as to the elevation of the point in question.

For rendering the unit numeral markers, E, conveniently removable fromthe face of the rod, they may each be provided with a dowel pin, Eprojecting from the rear face of the marker and adapted to fit snugly inthe holes, B and D arranged in the graduated face of each of thescale-bearing members at the unit marks of their scales. iVith eachleveling rod there will then be furnished a set of these markers, E,labeled from zero to nine, respectively, or by providing a double set ofsuch markers the unit points of the scale could be labeled to correspondwith both the tens and units digits of the number representing theelevation of the bench mark chosen as a base, it being understood thatwith the entire length of the extension member, D, in use, the levelingrod will ordinarily comprise a graduated length of ten feet.

I claim 1. A graduated leveling rod, having removable andinterchangeable numerals for the principal scale divisions thereof.

2. A graduated leveling rod having a channeled face and removable andinterchangeable marking plates adapted to be secured to the bottom ofsuch channel for indicating the principal scale divisions of the rod.

3. A graduated leveling rod comprising a nfiincipal member and anextension meniber slidably secured to the bark thereof, removable andinteichangeable markingplates for the priuci iwal scale divisions of therod, and means on both members for securing said marking plates, theextension member having a channeled face atlording space for the markingplates between said member and the principal member.

4. A graduated leveling rod and removable and interchangeable numeralplates for the principal scale divisions thereof, the rod being providedwith sockets at its principal graduations, and each of said plateshaving a projection formed to fit in such sockets.

A leveling rod comprising a graduated portion, a foot piece upon whichsaid portion is mounted for bodily vertical adjustment, and removableand interchangeable numerals for the principal scale divisions of thegraduated portion.

In testimony whereof I have hereunto set my hand at Chicago, Illinois,this 4:th day of March, 1913.

ERNEST S. MARTIN.

Witncsses A. V. MGAULEY, A. E. OLsoN.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

